Sumatriptan, recently introduced for the treatment of migraine, heralds the beginning of a molecular era in the pharmacological treatment of migraine headache. An indole (non-ergot alkaloid) derivative with agonist properties at a receptor resembling the 5-HT1D subtype (so-called 5-HT1-like receptor), sumatriptan is the first antimigraine medication to exhibit receptor-selective properties. Clinical data indicate that sumatriptan relieves headache, nausea, and photophobia in a majority of acute migraine patients, and it possesses favorable side effect and safety profiles. Of great importance, sumatriptan acts through a novel mechanism that we now know is shared by dihydroergotamine and other useful compounds for the treatment of acute migraine headaches. In this summary, we briefly review the drug's mechanism of action and the emerging clinical experience with its use.